Electrolytic apparatus and method



M. M. MERRITT.

ELECTROLYTIC APPARATUS AND METHOD.

APPLICATION FILED Aue.2, 1918.

1,335,176. Patented Mar. 30,1920.

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n ll 5' \MIHIZAWM "II ll III Inventor .lia itheurjl Merriii UNITED STATES PATENT OFFICE.

MATTHEW M. MERRITT, OF SOUTH MIDDLETON, MASSACHUSETTS, ASSIGNOR TO COPPER PRODUCTSCOMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

ELECTROLYTIC APPARATUS AND METHOD.

Specification of Letters Patent.

Patented Mar. 30, 1920.

Application filed August a, 1918. Serial No. 247,967.

To all, whom? it may concern Be it known that I, llh'r'rlmw M. MER- RITT, a citizen of the United States, and a resident of South Middleton, county of Esratus used in connection with my invention; l

Fig. 2 is a side elevation thereof, partly in section, on thaline 22 of Fig. 1;

Fig. 3 is an enlarged view of the end of a propeller shown in Fig. 1;

Fig. 4 is a section on the line 41- 1 of Fig. 3; and

Fig. 5 is a view of a complete propeller and its associated apparatus as shown in n the drawings I have shown a tank 4 containing electrolyte 5, anodes 6, and having a horizontal rotatable shaft 7 mounted above the tank adapted to carry a plurality of aeroplane propellers 8 mounted thereon,

preferably in such relation as to form a helix, the shaft preferably being at such a height above the electrolyte that approximately one-third of a propeller can be immersed in the electrolyte. The shaft 7 is preferably rotated by any suitable mechanism, at such speed that the end portions of each propeller will be immersed approximately two seconds and emersed approximately four seconds.

The end of the propeller which is to be protected by electrolytic deposit is coated with electro-conductive material, preferably bronze powder and amyl-acetate. Adjacent the edge of the portion of the propeller to be coated I preferably provide a narrow band 9 of shellac or other non-conductive material, and adjacent the non-conductive band 9 I preferably provide a thief 10 which may conveniently be formed by a second band of conductive paint. The remainder of the propeller may be protected from the action of the acid in the electrolyte by parafiin or any other suitable acid-resisting substance. About those portions of the propeller which are to be coated, I preferably provide a framework 11 which for convenience may take the form of a box having the.

ends removed, and which may be secured in place in any suitable way, typified by the wedge-blocks 12 adjacent the hub of the propeller.

By the symmetrical positioning of the propellers about the shaft 7, the amount of electro-conductive surface immersed in the electrolyte is kept substantially constant as the shaft is revolved, thus preventing deleterious variation in the amount of current available for electro-deposit on any given surface at any time. The framework 11 causes the electrolyte to be stirred up in front of the surface on which deposition is to be made, and thereby not only tends to prevent the adhesion of dirt or occluded hydrogen on the cathode by increasing the washing action of the electrolyte, but also tends to minimize that increase of deposit which would otherwise take place on the front edge of the propeller as it revolved. The varnished band 9 gives a clean-cut edge to the electro-deposit, while the thief 10 V prevents a surplus of deposit on this edge or marginal portion. The thief 13 prevents excess deposit and consequent roughness and unevenness of the deposit adjacent the edges of the propeller asdistinguished from the edge or marginal portions of the tip which 'is protected by the thief 10.

It will be understood, of course, that the tips of the propellers and the thieves 10 and 13 should be connected by wires to the shaft 7, which is connected with any suitable source of current, thereby causing said portions to become cathodes, while the anodes are connected to the opposite pole of g st 2, 1918, Serialincntof my invention, and while I have desa'l'ibed a preferred way of practising my improved method, it will be understood that major changes in the apparatus and even changes in the method described may be madewithout departing from the scope of my invention, which is best defined in the following claims.

Claims:

l. The method of electrolytically depositing metal on segregated surfaces of objects which comprises mounting the objects on a rotatable shaft and rotating the shaft during electro-deposition while a portion only of the surfaces to be deposited upon are immersed in the electrolyte, whereby each surface is alternately immersed and emersed.

2. The method of electrolytically depositing metal on segregated surfaces of objects which comprises mounting the objects in distributed relation about a rotatable shaft, and rotating the shaft during electro-deposition while a portion only of the surfaces to be deposited upon are immersed in the electrolyte, whereby each surface is alternately immersed and emersed and while the area of immersed cathode surface is maintained substantially constant in area.

3. The method of depositing metal on a plurality of cathodes which comprises alternately, rapidly and repeatedly immersing and emersing each cathode in the electrolyte.

4. The method of depositing metal on a plurality of cathodes which comprises alternately, rapidly and repeatedly immersing and emersing each cathode in the electrolyte while maintaining substantially unchanged the aggregate immersed cathode area.

5. The method of depositing metal on a plurality of cathodes which comprises -mersion in the electrolyte and emersion therefrom.

6. The method of depositing metal on the tips of aeroplane propellers which comprises mounting the propellers in distributed relationship about a rotatable shaft and rotating the shaft and propellers under partial submergence in an electrolyte while stirring the electrolyte adjacent each propeller tip. a

'7. The method of, depositing metal on the tips of aeroplane propellers which comprises mounting the propellers in distributed relationship about a rotatable shaft and rotating the shaft and propellers under partial submergence in an electrolyte while each ropeller tip is preceded by a plow.

8. he method of depositing protecting metal on a propeller tip which comprises coating theend of the tip to be protected with an electrically conductive substance, the edge of the portion to be protected being defined by a band of non-conductive substance, and providing a removable conductive agent adjacent the edge of the portion to be protected, electrolytically depositing metal on the surface to be protected and on the removable conductive agent adjacent the edge thereof, and subsequently removing the removable conductive agent and the metal deposited thereon.

In testimony whereof I have signed my name to this s ecification.

MA THEW M. MERRITT. 

